title: The effect of levamisole on glycogen synthase and the metabolism of Litomosoides carinii.
abstract: The effects of the anthelmintic drug, levamisole, on glycogen metabolism in the adult filariid, Litomosoides carinii, were examined. Incubation of helminths for up to 6 hr in the presence of levamisole resulted in a fourfold increase in total worm glycogen levels. In accord with this observation, levamisole also produced an eightfold increase in the rate of incorporation of [14C]-glucose into [14C]-glycogen over a 6-hr incubation period. In contrast, levamisole had no significant effect on 14CO2 evolution or lactate formation from exogenous glucose indicating that glycolysis was not affected. Because levamisole stimulated the incorporation of [14C]-glucose into glycogen, its effects on glycogen synthase activity were determined. Glycogen synthase in L. carinii was found to exist in both glucose-6-phosphate dependent (D) and glucose-6-phosphate independent (I) forms. In vitro incubation of intact L. carinii for 2 hr in the presence of levamisole resulted in a significant increase in the activity ratio (activity in the absence of glucose-6-P divided by the activity in the presence of glucose-6-P). This suggests that levamisole may act to stimulate the conversion of the less active (D) form of the glycogen synthase to the more active (I) form.
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D005370:Filarioidea / Q000187:drug effects* / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism*; D006006:Glycogen Synthase / Q000378:metabolism*; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D007978:Levamisole / Q000494:pharmacology*
chemical_list: D007773:Lactates; D002245:Carbon Dioxide; D007978:Levamisole; D019344:Lactic Acid; D006003:Glycogen; D006006:Glycogen Synthase; D005947:Glucose